A second member is placed in abutment against a first member. An abutment site between the members is welded. From the conventional art, it is widely known to carry out such welding in order to unite the two members in an integral manner.
In carrying out welding, in recent years, a laser beam with high energy density has been used.
With such a laser beam, a technique is known in which curved surfaces are welded together (for example, refer to Patent Document 1).
The technique of Patent Document 1 will be described with reference to FIG. 9.
As shown in FIG. 9, two steel pipes 101, 101 are oriented in front and rear directions of the drawing and are placed together in abutment. The steel pipes 101 are surrounded by an annular guide rail 102. A processing head 103 is mounted movably on the guide rail 102. A laser gun 104 is mounted on the processing head 103 so as to face toward a center 105 of the steel pipes 101. While the processing head 103 is moved along the guide rail 102, a laser beam is irradiated from the laser gun 104 and laser welding is carried out.
The laser beam is irradiated perpendicularly to the curved surface, and therefore, high quality welding can be implemented with favorable weld penetration.
The processing head 103 undergoes movement. On the other hand, a laser oscillator 106 does not move. Therefore, the laser oscillator 106 and the processing head 103 are tethered together via a laser transmitting device 110 including first through third joints 107, 108, 109.
The first through third joints 107, 108, 109 are essential elements, and therefore, the laser welding device according to Patent Document 1 is complex in structure and large in size. As a result, installation costs for such welding equipment increase.
In addition, since the structure is complex, the number of constituent elements increases, and maintenance costs that occur accompanying the replacement of such components tend to rise precipitously.
While seeking a reduction in processing costs, a laser welding device has been desired, which is both simple in structure and small in scale, even in the case of a device that enables welding of curved surfaces.